homeostasis mrs. harlin. 1.2.1 explain how homeostasis is maintained in the cell and within an...
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1.2.1
Explain how homeostasis is maintained in the cell and within an organism in various environments (including temperature and pH).
HomeostasisHomeostasis is a state of maintaining an
internal balance within cells.Cells use buffers to regulate cell pH.Cells respond to maintain temperature, glucose
levels, and water balance.
1. Passive TransportRequires no
energy to move across a membrane.
Goes with the concentration gradient.
DiffusionThe movement of a substance from an area of
high concentration to an area of low concentration.
Diffusionhttp://highered.mcgraw-hill.com/sites/
0072495855/student_view0/chapter2/animation__how_diffusion_works.html
Osmosishttp://highered.mcgraw-hill.com/sites/
0072495855/student_view0/chapter2/animation__how_osmosis_works.html
Scenario 1If the concentration of substances in the
solution is the same as inside the cell. Water constantly moves in and out of the cell.No shape change.Equilibrium is reached.
Scenario 2Higher concentration inside the cell. Water moves IN the cell in attempt to reduce
the concentration- swelling
Animal cells may burst if too much water comes in! Called lysis.
Plant cells will only become more and more firm.
Scenario 3Higher concentration outside the cell than
inside.Water will move OUT in attempt to reduce
the outside concentration.Cells will shrivel and shrink. Plants will wilt.Ex: When you put salt on a slug, it shrinks
and dies.
2. Active TransportRequires energy. Uses the carrier proteins
to change shape in order pass a particle.
Substances can either go with or against the concentration gradient.
Examples- Endocytosis, exocytosis, Sodium-Potassium Pump
Sodium-Potassium Pumphttp://highered.mcgraw-hill.com/sites/
0072495855/student_view0/chapter2/animation__how_the_sodium_potassium_pump_works.html
Facilitated DiffusionType of passive or
active transport across a membrane with using a transport protein.
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